Performance of RC Beam Strengthened with NSM-CFRP Strip Under Pure Torsion: Experimental and Numerical Study

This paper presents experimental and finite element model (FEM) on reinforced concrete (RC) beam behavior strengthened by near-surface mounted (NSM) carbon fiber-reinforced polymer (CFRP) strips subjected to pure torsional loading. Seven rectangular reinforced concrete RC beams of 250 mm × 250 mm × 1600 mm were constructed and tested considering the effect of length, inclination, arrangement of longitudinal and scheme of NSM-CFRP strips. The outcomes of the tests indicated remarkable enhancement in the behavior of torsional strengthened beams using NSM-CFRP strips. In general, the beams strengthening with inclined CFRP-NSM strips exhibited an increase in torsion moment strength and angle of twist more than the beams strengthening with vertical CFRP-NSM strips. The experimental measured results are validated with a 3D numerical simulation carried out using nonlinear finite element (FE) modeling. Finally, it can be seen that the calculated numerical torsional moment–angle of twist behavior is in agreement with the experimental results for all RC beams.